1. Field of the Disclosure
The disclosure relates generally to retractable instruments and more specifically to cap-less, retractable writing instruments having a valve door with a force directing component.
2. Related Technology
One example of a cap-less, retractable writing instrument is shown in U.S. Pat. No. 5,048,990, which is hereby incorporated by reference. The cap-less writing instrument includes a writing member having a writing tip. The writing member is accommodated in a seal cylinder that is disposed inside a writing instrument body. A seal cover for closing an end opening of the seal cylinder is disposed on the seal cylinder near the front end of the seal cylinder. A writing member moving mechanism moves the writing member forwardly and locks the writing member at a writing position with the writing tip protruding through the front of the writing instrument body. The moving mechanism includes a thread-like member that connects the writing member to the seal cover so that after the writing member is retracted, the seal cover is pulled backwardly so as to be brought into contact with the seal cylinder, thus preventing the writing tip from drying out. The prior art cap-less writing instruments work well with relatively small writing tips. However, the prior art design is not especially well suited for relatively large writing tips, for example, those used to produce markers intended to convey information to groups of people such as dry erase markers, and other similarly sized markers, as the seal cover does not adequately seal large diameter openings.